package priv.pront.code.lanqiao.competition.course.date0330;

import java.util.Scanner;

public class 刷题统计 {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long a = sc.nextLong();
        long b = sc.nextLong();
        long n = sc.nextLong();

        long z = a * 5 + b * 2;
        long count = (n / z) * 7;
        long sum = (n / z) * z;

        long[] arr = { a, a, a, a, a, b, b };
        for (int i = 0; i < arr.length; i++) {
            if (sum >= n) {
                break;
            } else {
                sum += arr[i];
                count++;
            }
        }
        System.out.println(count);

    }

}
